This invention relates to manual actuators for a multifunction system as, for example, a lever movable fore and aft to control one function of the system and from side to side to control another function of the system.
Manual actuators for multifunction systems have been employed in a wide variety of applications. Perhaps the most common application is in controlling work performing vehicles such as crawler tractors, lift trucks, excavators, and the like. For example, a single actuator may be movable fore and aft to control direction of movement of a vehicle and side-to-side to control some other function of the vehicle as, for example, turning characteristics or the movement of a work performing means. Through the use of such actuators, operation of such vehicles or the like has been considerably simplified in that the operator need not literally "hunt" for individual actuators for each function performed by the system since one actuator may be manipulated to perform two or more functions.
Frequently, there is a need for detenting the actuator in a particular position corresponding to a command to perform a particular function. Not infrequently, such detenting is accomplished through the use of detents within a system element being controlled by the actuator such as, for example, a hydraulic valve. Where cables interconnect the actuator and the element actuated thereby, such a construction presents difficulties in that the cable must not only be sufficiently strong so as to convey actuator movement to the element being controlled, but it must be sufficiently strong so as to transmit the additional force required to move the controlled element in and out of its detented position. Frequently, too, the requirement that force be transmitted through cables to the element being controlled to overcome a detent associated therewith increases the manual effort required to operate the manual actuator.
Finally, in many cases, extremely complicated cable and/or linkages are necessary to achieve interconnection between the actuator and the elements to be controlled thereby.